I connect the cables directly to the battery(donor first) BUT the donor is never running, so generally no spark is created(unless the donoee is totally dead)... I only start engine after the cables are connected, then let it run a couple minutes before trying to start the donoee(yeah isn't really a word)...
Tell me how by jumping a battery you can screw up
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I've always been worried that the donor car won't start... It's not as if my car always has a new battery in it! But I guess it should have no problems cranking, can't get that much juice down the cable in that short of a time. I should try that next time.
Donor car will have advantage of warm oil and fuel vapors in the intake manifold; it should restart pretty easily. After all it was just running to pull up to the dead car, right?
The one thing you should never jump with a running donor is a motorcycle; their simple voltage regulators turn extra amperage above 13.5 volts to heat and their cheapo charging systems are sized for ignition plus a headlight, not 100 amps. Hook up a running car and you'll let the magic smoke out of the VR. Realistically a dead bike can usually be roll (or kick) started.
The one thing you should never jump with a running donor is a motorcycle; their simple voltage regulators turn extra amperage above 13.5 volts to heat and their cheapo charging systems are sized for ignition plus a headlight, not 100 amps. Hook up a running car and you'll let the magic smoke out of the VR. Realistically a dead bike can usually be roll (or kick) started.
Fuel vapors in the intake manifold? Not on any late model EFI motor since, what, 1995? All dry intakes I thought, or for the most part. Plus I drive a diesel, I sure hope there is no fuel vapors in my intake manifold!
Point taken, although two of the times I've had bad batteries the vehicle would run fine after a jump. It just wouldn't start after sitting 10-15 minutes (but IIRC it would crank over on an immediate restart). Since I have the nasty habit of waiting until the battery needs replacement...
Point taken, although two of the times I've had bad batteries the vehicle would run fine after a jump. It just wouldn't start after sitting 10-15 minutes (but IIRC it would crank over on an immediate restart). Since I have the nasty habit of waiting until the battery needs replacement...
Friend of mine blew up a dead lawnmower battery trying to jump it with a car.
When I was in FutureCar competition, the staff told us about an incident that happens 1 day earlier when a team member from another university was wrenching the battery and slip his wrench, shorting the POS and NEG through his wrench when he was holding it.
The short generate such a huge amount of current and heat, that gave his hand a Nth degree burn, plus the explosion from the hydrogen knock him off a few feet away.
That's how I learn to always disconnect the NEG first, then shield the NEG when I work on the POS, then shield the POS when connecting the NEG, so nothing can accidentally short.
The short generate such a huge amount of current and heat, that gave his hand a Nth degree burn, plus the explosion from the hydrogen knock him off a few feet away.
That's how I learn to always disconnect the NEG first, then shield the NEG when I work on the POS, then shield the POS when connecting the NEG, so nothing can accidentally short.
Originally Posted By: PandaBear
That's how I learn to always disconnect the NEG first, then shield the NEG when I work on the POS, then shield the POS when connecting the NEG, so nothing can accidentally short.
That is a GREAT point. I never went to the trouble to shield the negative terminal when disconnecting the positive cable from thje terminal, but that is a excellent idea. So what do you use to shield the terminal?
That's how I learn to always disconnect the NEG first, then shield the NEG when I work on the POS, then shield the POS when connecting the NEG, so nothing can accidentally short.
That is a GREAT point. I never went to the trouble to shield the negative terminal when disconnecting the positive cable from thje terminal, but that is a excellent idea. So what do you use to shield the terminal?
Note new car batteries that have post shields on them.
Originally Posted By: antiqueshell
So what do you use to shield the terminal?
I save the plastic cap of new battery's terminal for this purpose.
So what do you use to shield the terminal?
I save the plastic cap of new battery's terminal for this purpose.
Helped out someone who had ran his battery down and said AAA wont boost him because he had a hybrid, I boosted him np but found later that if his gizmo started instead of the ICE my electrical system could've been fried.
I will never boost someone with a frozen dead battery.
I will never boost someone with a frozen dead battery.
Originally Posted By: Miller88
Friend of mine blew up a dead lawnmower battery trying to jump it with a car.
I did this just this week. I hate jumping batteries, but do it all the time. Luckily, the lawnmower jump went OK.
Friend of mine blew up a dead lawnmower battery trying to jump it with a car.
I did this just this week. I hate jumping batteries, but do it all the time. Luckily, the lawnmower jump went OK.
. . . on a negative-ground system, the LAST connection is ALWAYS negative to the chassis/designated engine point on the serviced vehicle, NEVER to the battery. As an extra precaution, we just don't ever make connections to the negative on EITHER battery. Chassis to chassis always.
Even then, with some of the newer ones, there is always a risk of computer damage with jumps or boosters. If you have roadside service, make them do it.
We've been fortunate to never have had one blow on us. But I've heard enough stories from colleagues to know you don't ever want it to happen. Sulfuric acid is horrific.
Even then, with some of the newer ones, there is always a risk of computer damage with jumps or boosters. If you have roadside service, make them do it.
We've been fortunate to never have had one blow on us. But I've heard enough stories from colleagues to know you don't ever want it to happen. Sulfuric acid is horrific.
^Wow. Really? Negative to chassis on both? I usually just do that to the battery on the vehicle needing a jump.
Negative to chassis on the car being jumped has the added benefit other than safety of eliminating the rotten/corroded/oxidized/overheated negative battery cable from the circuit, delivering higher voltage to the starter. On vehicles where the starter solenoid is easily accessed [farm & const. equ., semi tractors, old Fords] I connect directly to the solenoid as well on the vehicle being jumped.
JHZR2
Staff member
Originally Posted By: wirelessF
I had jumper cables but it was too short if you want to jump someone from behind.
Do you tie them up with the cables or choke them?
hahahaha. ugh. Long day.
I had jumper cables but it was too short if you want to jump someone from behind.
Do you tie them up with the cables or choke them?
hahahaha. ugh. Long day.
Random thoughts on jumping batteries.
An over charged car battery is dangerous. It is not the common mode of failure, but it does happen. I have a set of 2 awg cables in every car. All your safety precautions are good things to do. What follows below is a cautionary tale. Do not be this fool.
Miraculously, I have survived just going pole to pole. In the correct polarity. Make the final clamp at the donor battery. Engine off, if it is a simple dead battery and the rest of the charging system works..
Quick and dirty battery test is to cross the leads. A crack and a blue spark is a good connection then go find the battery under the hood of the dead car.
It is snowing , the light is bad. You are in a hurry. At least double check the polarity. If you smell rotten eggs,it is get a new battery in there before starting the car.
My jump pack has an on/off switch and a polarity light on it. I guess they had to take steps to idiot proof it.
An over charged car battery is dangerous. It is not the common mode of failure, but it does happen. I have a set of 2 awg cables in every car. All your safety precautions are good things to do. What follows below is a cautionary tale. Do not be this fool.
Miraculously, I have survived just going pole to pole. In the correct polarity. Make the final clamp at the donor battery. Engine off, if it is a simple dead battery and the rest of the charging system works..
Quick and dirty battery test is to cross the leads. A crack and a blue spark is a good connection then go find the battery under the hood of the dead car.
It is snowing , the light is bad. You are in a hurry. At least double check the polarity. If you smell rotten eggs,it is get a new battery in there before starting the car.
My jump pack has an on/off switch and a polarity light on it. I guess they had to take steps to idiot proof it.
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